Semiconductor package having dummy pads and method of manufacturing semiconductor package having dummy pads

ABSTRACT

A semiconductor package includes a package substrate, a plurality of package terminals disposed on the bottom surface of the package substrate, and an interposer substrate disposed on the top surface of the package substrate, a plurality of interposer terminals disposed on the bottom surface of the interposer substrate and electrically connected to the package substrate, a first semiconductor chip disposed on the top surface of the interposer substrate, a second semiconductor chip disposed on the top surface of the interposer substrate and disposed to be horizontally separated from the first semiconductor chip, a first plurality of signal pads disposed on the top surface of the interposer substrate and electrically connected to wiring in the interposer substrate and one or more circuits in the first semiconductor chip, a second plurality of signal pads disposed on the top surface of the interposer substrate and electrically connected to wiring in the interposer substrate and to one or more circuits in the second semiconductor chip, and a plurality of dummy pads disposed outside of an area occupied by the first semiconductor chip or the second semiconductor chip from a top-down view and disposed on the top surface of the interposer substrate. Each pad of the first plurality of signal pads and the second plurality of signal pads is configured to transfer signals between the interposer substrate and a respective semiconductor chip, and each pad of the dummy pads is not configured to transfer signals between the interposer substrate and any semiconductor chip disposed thereon.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 to Korean Patent Application No. 10-2019-0081352, filed onJul. 5, 2019, in the Korean Intellectual Property Office, the entirecontents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present disclosure relates to a semiconductor package, and inparticular, to a semiconductor package in which a first die and a seconddie are disposed side by side on an interposer substrate.

In the semiconductor industry, various package technologies have beendeveloped to meet demands for large storage, thin thickness, and smallsize of semiconductor devices and/or electronic appliances. In the casewhere an integrated circuit (IC) chip is embedded in a semiconductorpackage, it is possible to easily use the IC chip as a part of anelectronic product. The semiconductor package may generally include aprinted circuit board (PCB) and a semiconductor chip which is providedon and electrically connected to the PCB through a bonding wire or abump. As the semiconductor industry matures, there is an increasingdemand for high-performance, high-speed, and compact semiconductorpackages.

SUMMARY

An embodiment of the inventive concept provides a semiconductor packagewith improved electrical characteristics.

According to some embodiments, a semiconductor package is provided. Thesemiconductor package includes a package substrate having a bottomsurface and a top surface, a plurality of package terminals disposed onthe bottom surface of the package substrate, and an interposer substratedisposed on the top surface of the package substrate, the interposersubstrate having a bottom surface facing the package substrate and a topsurface opposite the bottom surface. The semiconductor package alsoincludes a plurality of interposer terminals disposed on the bottomsurface of the interposer substrate and electrically connected to thepackage substrate, a first semiconductor chip disposed on the topsurface of the interposer substrate, a second semiconductor chipdisposed on the top surface of the interposer substrate and disposed tobe horizontally separated from the first semiconductor chip, a firstplurality of signal pads disposed on the top surface of the interposersubstrate and electrically connected to wiring in the interposersubstrate and one or more circuits in the first semiconductor chip, asecond plurality of signal pads disposed on the top surface of theinterposer substrate and electrically connected to wiring in theinterposer substrate and to one or more circuits in the secondsemiconductor chip, and a plurality of dummy pads disposed outside of anarea occupied by the first semiconductor chip from a top-down view andoutside of an area occupied by the second semiconductor chip from atop-down view and disposed on the top surface of the interposersubstrate. The first plurality of signal pads, the second plurality ofsignal pads, and the plurality of dummy pads are all located at the samevertical height above the top surface of the package substrate. Inaddition, each pad of the first plurality of signal pads and the secondplurality of signal pads is configured to transfer signals between theinterposer substrate and a respective semiconductor chip, and each padof the dummy pads is not configured to transfer signals between theinterposer substrate and any semiconductor chip disposed thereon.

According to some embodiments, which may be the same or differentembodiments as described above, A semiconductor package is provided. Thesemiconductor package includes a package substrate having a bottomsurface and a top surface, a plurality of package terminals disposed onthe bottom surface of the package substrate, and an interposer substratedisposed on the top surface of the package substrate, the interposersubstrate having a bottom surface facing the package substrate and a topsurface opposite the bottom surface. A plurality of interposer terminalsare disposed on the bottom surface of the interposer substrate andelectrically connected to the package substrate. A first semiconductorchip is disposed on the top surface of the interposer substrate, and asecond semiconductor chip is disposed on the top surface of theinterposer substrate and is disposed to be horizontally separated fromthe first semiconductor chip. A first plurality of signal pads aredisposed on the top surface of the interposer substrate and areelectrically connected to wiring in the interposer substrate and one ormore circuits in the first semiconductor chip. A second plurality ofsignal pads are disposed on the top surface of the interposer substrateand are electrically connected to wiring in the interposer substrate andto one or more circuits in the second semiconductor chip. A plurality ofdummy pads are disposed outside of an area occupied by the firstsemiconductor chip from a top-down view and outside of an area occupiedby the second semiconductor chip from a top-down view and are disposedon the top surface of the interposer substrate. The first plurality ofsignal pads, the second plurality of signal pads, and the plurality ofdummy pads are all located at the same vertical height above the topsurface of the package substrate, and a set of dummy pads of theplurality of dummy pads are outside of an area occupied by an outerboundary of outermost interposer terminals of the interposer substrate,from a top-down view.

According to some embodiments, a method of manufacturing a semiconductorpackage includes providing a package substrate having a bottom surfaceand a top surface, providing a plurality of package terminals on thebottom surface of the package substrate, and providing an interposerincluding an interposer substrate having a top surface and a bottomsurface. The interposer includes a plurality of interposer terminalsdisposed on the bottom surface of the interposer substrate, a firstplurality of signal pads disposed on the top surface of the interposersubstrate to occupy a first area of the interposer substrate, andelectrically connected to wiring in the interposer substrate, the firstplurality of signal pads for electrically connecting to one or morecircuits in a first semiconductor chip, a second plurality of signalpads disposed on the top surface of the interposer substrate to occupy asecond area of the interposer substrate, the second area horizontallyseparate from the first area, the second plurality of signal padselectrically connected to wiring in the interposer substrate and forelectrically connecting to one or more circuits in a secondsemiconductor chip, and a plurality of dummy pads disposed outside ofthe first area and the second area from a top-down view and disposed onthe top surface of the interposer substrate. The method further includesmounting the interposer on the top surface of the package substrate sothat the plurality of interposer terminals are between the interposersubstrate and the package substrate, and performing a heat bondingprocess to bond the interposer substrate to the package substratethrough the interposer terminals. The heat bonding process includesapplying heat and pressure to the interposer substrate by pressing aheat-bonding head on the top surface of the interposer substrate andheating the first plurality of signal pads, the second plurality ofsignal pads, and the plurality of dummy pads.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingbrief description taken in conjunction with the accompanying drawings.The accompanying drawings represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a perspective view illustrating a semiconductor packageaccording to an embodiment of the inventive concept.

FIG. 2 is a sectional view of the semiconductor package of FIG. 1,according to an example embodiment.

FIG. 3 is an enlarged sectional view of a portion ‘M’ of FIG. 2,according to an example embodiment.

FIG. 4 is an enlarged sectional view of a portion (e.g., the portion ‘M’of FIG. 2) of a semiconductor package according to an embodiment of theinventive concept.

FIGS. 5 and 6 are sectional views illustrating a method of fabricating asemiconductor package (e.g., of FIG. 1) according to an embodiment ofthe inventive concept.

FIG. 7 is a sectional view illustrating a method of fabricating asemiconductor package, according to a comparative embodiment of theinventive concept.

FIG. 8 is a perspective view illustrating a semiconductor packageaccording to an embodiment of the inventive concept.

FIG. 9 is a sectional view of the semiconductor package of FIG. 8,according to an example embodiment.

FIG. 10 is a plan view illustrating a semiconductor package according toan embodiment of the inventive concept.

FIG. 11 is a plan view illustrating a first surface of an interposersubstrate of FIG. 10, according to an example embodiment.

FIG. 12 is a sectional view taken along a line I-I′ of FIG. 10,according to an example embodiment.

FIG. 13 is a flow chart illustrating an example method of manufacturinga semiconductor package in accordance with certain embodiments.

It should be noted that these figures are intended to illustrate thegeneral characteristics of methods, structure and/or materials utilizedin certain example embodiments and to supplement the written descriptionprovided below. These drawings are not, however, to scale and may notprecisely reflect the precise structural or performance characteristicsof any given embodiment, and should not be interpreted as limiting therange of values or properties encompassed by example embodiments. Forexample, the relative thicknesses and positioning of molecules, layers,regions and/or structural elements may be reduced or exaggerated forclarity. The use of similar or identical reference numbers in thevarious drawings is intended to indicate the presence of a similar oridentical element or feature.

DETAILED DESCRIPTION

Example embodiments of the inventive concepts will now be described morefully with reference to the accompanying drawings, in which exampleembodiments are shown.

FIG. 1 is a perspective view illustrating a semiconductor packageaccording to an embodiment of the inventive concept. FIG. 2 is asectional view of the semiconductor package of FIG. 1. FIG. 3 is anenlarged sectional view of a portion ‘M’ of FIG. 2.

Referring to FIGS. 1 to 3, a package substrate PSUB may be provided. Aninterposer substrate IPS may be provided on the package substrate PSUB.As an example, the package substrate PSUB may be a printed circuit board(PCB). The interposer substrate IPS may be a redistribution layersubstrate.

The interposer substrate IPS may have a first surface IPSa (e.g., a topsurface) and a second surface IPSb (e.g., a bottom surface), which areopposite to each other. The second surface IPSb may face the packagesubstrate PSUB (e.g., a top surface of the package substrate PSUB).First outer terminals BP, also described as interconnection terminals,or interposer terminals, may be provided on the second surface IPSb ofthe interposer substrate IPS, to be located at an external surface ofthe interposer substrate IPS and communicate outside of the interposersubstrate IPS. The first outer terminals BP may be interposed betweenthe interposer substrate IPS and the package substrate PSUB, andtherefore may electrically connect to the interposer substrate IPS andthe package substrate PSUB. For example, the first outer terminals BPmay include conductive bumps.

Second outer terminals SB, also described as external connectionterminals, or package terminals, may be provided on a bottom surface ofthe package substrate PSUB. The second outer terminals SB may include,for example, solder balls. Although not shown, the package substratePSUB may include routing lines and at least one via, which are providedtherein.

The first surface IPSa of the interposer substrate IPS may include afirst signal region SPR1, a second signal region SPR2, a connectionregion CNR, and a peripheral region PPR. The first signal region SPR1and the second signal region SPR2 may be disposed side by side in asecond direction D2. The second signal region SPR2 may be spaced apartfrom the first signal region SPR1 in the second direction D2. Theconnection region CNR may be interposed between the first signal regionSPR1 and the second signal region SPR2.

The peripheral region PPR may be a remaining region of the first surfaceIPSa, other than the first signal region SPR1, the second signal regionSPR2, and the connection region CNR. The first signal region SPR1, thesecond signal region SPR2, and the connection region CNR may be locatedin an inner region of the first surface IPSa. The peripheral region PPRmay be located in an edge region of the first surface IPSa. Theperipheral region PPR may be provided to enclose and to be outside ofthe first signal region SPR1, the second signal region SPR2, and theconnection region CNR.

A first die DIE1 and a second die DIE2 may be provided on the firstsurface IPSa of the interposer substrate IPS. The first die DIE1 and thesecond die DIE2 may be mounted on the interposer substrate IPS to bedisposed side by side in the second direction D2. The first die DIE1 andthe second die DIE2 may be mounted on the first signal region SPR1 andthe second signal region SPR2, respectively. Each of the first die DIE1and the second die DIE2 may be a logic die including a centralprocessing unit or a memory die including a memory cell, and may bedescribed as a semiconductor chip, which includes an integrated circuitformed thereon.

The first die DIE1 may include a first substrate SUB1 and a first activelayer ACL1 on the first substrate SUB1. The first active layer ACL1 mayinclude transistors, which are formed on the first substrate SUB1, andinterconnection layers, which are provided on the transistors (e.g., ona first surface of the first substrate SUB1 facing the interposersubstrate IPS). The second die DIE2 may include a second substrate SUB2and a second active layer ACL2, which is provided on the secondsubstrate SUB2. The second active layer ACL2 may include transistors,which are formed on the second substrate SUB2, and interconnectionlayers, which are provided on the transistors (e.g., on a first surfaceof the second substrate SUB2 facing the interposer substrate IPS).

The first die DIE1 may be mounted on the interposer substrate IPS in aface-down manner, in which the first active layer ACL1 faces a firstsurface IPSa of the interposer substrate IPS. The second die DIE2 may bemounted on the interposer substrate IPS in a face-down manner, in whichthe second active layer ACL2 faces the first surface IPSa of theinterposer substrate IPS.

Signal pads SPD may be provided on the first signal region SPR1 and thesecond signal region SPR2. For example, a plurality of the signal padsSPD may be provided on the first signal region SPR1, and a plurality ofthe signal pads SPD may be provided on the second signal region SPR2.Signal pads, as described herein, are positioned in a location, and areused, for transmitting signals between two devices or circuits which thesignal pads connect. Each signal pad SPD is configured to transfersignals between the interposer substrate and a respective semiconductorchip. The various pads described herein may be provided on or near anexternal surface of the device on which they are formed, and maygenerally have a planar surface area. The pads may be formed of aconductive material, such a metal including one or more of Au, Ni, Cu,or Al, for example, formed in one or more layers.

Connection terminals IM may be respectively interposed between the firstdie DIE1 and the signal pads SPD on the first signal region SPR1. Theconnection terminals IM may be interposed between the second die DIE2and the signal pads SPD on the second signal region SPR2. The connectionterminal IM may be disposed on each of the signal pads SPD. The firstand second dies DIE1 and DIE2 and the interposer substrate IPS may beelectrically connected to each other through the connection terminals IMand the signal pads SPD. For example, each signal pad SPD for the firstdie DIE1 or for the second die DIE2 may be disposed on the top surfaceof the interposer substrate IPS. As an example, the connection terminalsIM may include micro bumps.

The signal pads SPD on the first signal region SPR1 (e.g., a firstplurality of signal pads) may be used to exchange at least one of datasignals, command signals, or access signals between the first die DIE1and the interposer substrate IPS, and are therefore electricallyconnected to wiring in the interposer substrate IPS and one or morecircuits in the first die DIE1. The signal pads SPD on the second signalregion SPR2 (e.g., a second plurality of signal pads) may be used toexchange at least one of data signals, command signals, or accesssignals between the second die DIE2 and the interposer substrate IPS,and are therefore electrically connected to wiring in the interposersubstrate IPS and one or more circuits in the second die DIE2. Forexample, each of the signal pads SPD may serve as a path to transmit atleast one of data, command, or access signals.

The first and second dies DIE1 and DIE2 may be mounted on the interposersubstrate IPS in a flip-chip bonding manner by the connection terminalsIM, and may be horizontally separated from each other. Although notshown, a region between the first and second dies DIE1 and DIE2 and theinterposer substrate IPS may be filled with an under-fill resin layer.

The first and second dies DIE1 and DIE2 may be electrically connected toeach other through the interposer substrate IPS. At least one of data,command, or access signals may be exchanged between the first and seconddies DIE1 and DIE2 through the interposer substrate IPS.

Hereinafter, the interposer substrate IPS will be described in moredetail. The interposer substrate IPS may include a first insulatinglayer IPS1, a second insulating layer IPS2 on the first insulating layerIPS1, and a third insulating layer IPS3 below the first insulating layerIPS1. The first insulating layer IPS1 may be interposed between thesecond and third insulating layers IPS2 and IPS3, and may be a corelayer (e.g., a non-conductive core layer). The first insulating layerIPS1 may in some embodiments be formed of undoped silicon, and thereforemay serve as an insulating layer even though it is formed of asemiconductor material. Or it may be formed of another insulatingmaterial. The layers IPS1, ISP2, and IPS3 may also be described asnon-conductive layers.

A conductive structure CS may be provided in the second insulating layerIPS2. The conductive structure CS may include a plurality of conductivelines CL and a plurality of vias VI (e.g., conductive vias). The via VImay connect one of the conductive lines CL thereon to another of theconductive lines CL thereunder. The signal pad SPD on the first signalregion SPR1 may be electrically connected to the signal pad SPD on thesecond signal region SPR2 through the conductive structure CS. In otherwords, the signal pads SPD may be electrically connected to each otherthrough the conductive structure CS of the interposer substrate IPS. Theconductive line CL, which electrically connects the first and seconddies DIE1 and DIE2 to each other, may constitute a signal line. Thesignal line may be disposed in the connection region CNR of theinterposer substrate IPS. The connection region CNR may be horizontallybetween the first die DIE1 and the second die DIE2. Conductive lines maybe formed in or on the interposer substrate in the first connectionregion CNR. In addition, in some embodiments, no dummy pads are formedon the top surface of the interposer substrate IPS above the conductivelines in the first connection region CNR.

Conductive pads CPD may be provided in the third insulating layer IPS3.The third insulating layer IPS3 may cover the conductive pads CPD. Thefirst outer terminals BP may be provided on the conductive pads CPD,respectively. The first outer terminal BP may be interposed between theconductive pad CPD and the package substrate PSUB.

Through vias TV may be provided in the first insulating layer IPS1. Thethrough vias TV may penetrate the first insulating layer IPS1. Thethrough vias TV may electrically connect the conductive structure CS tothe conductive pads CPD, and may be referred to as conductive throughvias.

Dummy pads DPD may be provided on the peripheral region PPR. The dummypads DPD may be electrically disconnected from the first and second diesDIE1 and DIE2. For example, the connection terminal IM may not beprovided on each of the dummy pads DPD. The dummy pads DPD may beexposed to the air during manufacturing after the first and second diesDIE1 and DIE2 have been mounted on the interposer substrate IPS, and maybe covered with a protection layer or a mold layer (e.g., moldingmaterial) in a finished product. For example, the dummy pads DPD may becovered with an insulating material, and may not be electricallyconnected to any other conductive material. In some embodiments, thedummy pads DPD are not positioned, connected, or configured to transmitor receive signals between two devices or circuits (such as between theinterposer substrate IPS and any semiconductor chip disposed thereon),and thus dummy pads are not signal pads. In some embodiments, the dummypads are electrically isolated from any wiring or circuits in theinterposer substrate. Furthermore, as can be seen in FIGS. 1 and 2, thedummy pads DPD may have a bottom surface facing the interposer substrateIPS and a top surface facing away from the interposer substrate IPS, andthe top surface of each dummy pad DPD contacts an insulating materialand does not contact an electrically conductive material. In someembodiments, the bottom surface of each dummy pad DPD also contacts ininsulating material and does not contact an electrically conductivematerial.

In some embodiments (not shown), each dummy pad of the plurality ofdummy pads is connected to a dummy TSV (through substrate via) passingthrough the interposer substrate IPS.

The dummy pads DPD may be arranged in the second direction D2. A pitchbetween the dummy pads DPD arranged in the second direction D2 may be afirst pitch PI1. The first pitch PI1 may range from 40 μm to 200 μm. Thesignal pads SPD may be arranged in the second direction D2. A pitchbetween the signal pads SPD arranged in the second direction D2 may be asecond pitch PI2. As an example, the first pitch PI1 may be greater thanthe second pitch PI2. As another example, the first pitch PI1 may beequal to or smaller than the second pitch PI2. In one exampleembodiment, the first pitch PI1 has a value between about 40 μm andabout 200 μm, and the second pitch PI2 has a value between about 30 μmand about 150 μm. In this case, in one embodiment, the first pitch PI1may be greater than the second pitch PI2. In some embodiments, the dummypads DPD are arranged in first and second directions respectivelyparallel to a first edge of the interposer substrate IPS and a secondedge of the interposer substrate IPS perpendicular to the first edge. Inaddition, adjacent dummy pads in each of the first direction and seconddirection may be separated from each other by no more than 200 μm.

The signal pads SPD on the first signal region SPR1 may verticallyoverlap the first die DIE1. The signal pads SPD on the second signalregion SPR2 may vertically overlap the second die DIE2. The dummy padsDPD in certain embodiments do not vertically overlap the first andsecond dies DIE1 and DIE2. When viewed in a plan view, the dummy padsDPD may be spaced apart from the first and second dies DIE1 and DIE2 tobe outside of an area surrounding both the first die DIE1 and the seconddie DIE2. In this manner, a plurality of dummy pads DPD are disposedoutside of an area occupied by a first semiconductor chip (e.g., firstdie DIE1) from a top-down view and outside of an area occupied by thesecond semiconductor chip (e.g., second die DIE2) from a top-down view,and are disposed on the top surface of the interposer substrate IPS. Aset of dummy pads of the plurality of dummy pads DPD may be outside ofan area occupied by an outer boundary of outermost interposer externalterminals BP of the interposer substrate. In some embodiments, a firstplurality of signal pads are arranged in first and second directionsrespectively parallel to a first edge of the interposer substrate IPSand a second edge of the interposer substrate IPS perpendicular to thefirst edge, and adjacent signal pads of the first plurality of signalpads in each of the first direction and second direction are separatedfrom each other.

In certain embodiments, the dummy pads DPD are not connected to anyconductive structure CS of the interposer substrate IPS. Therefore, thedummy pads DPD may be electrically disconnected from each other and fromother signal-transmitting circuitry or conductive elements of thepackage. The dummy pads DPD may be electrically disconnected from anysignal pads SPD.

The signal pads SPD may not be provided on the peripheral region PPR.For example, the signal pads SPD may be spaced apart from the peripheralregion PPR. The signal pads SPD and the dummy pads DPD may not beprovided on the connection region CNR. For example, the signal and dummypads SPD and DPD may be spaced apart from the connection region CNR. Inone embodiment, regarding pads located at the first surface IPSa of theinterposer substrate IPS, only the signal pads SPD are selectivelyprovided on the first and second signal regions SPR1 and SPR2, and onlythe dummy pads DPD are selectively provided on the peripheral regionPPR. In some embodiments, a first plurality of signal pads (e.g. signalpads in the first signal region SPR1), a second plurality of signal pads(e.g. signal pads in the second signal region SPR2), and the pluralityof dummy pads DPD are all located at the same vertical height above thetop surface of the package substrate PSUB.

Referring back to FIG. 2, the interposer substrate IPS may have a firstsidewall SW1 and a second sidewall SW2, which are opposite to each otherin the second direction D2. A first dummy pad DPD1 of the dummy pads DPDmay be adjacent to the first sidewall SW1. An outermost terminal BP1 ofthe first outer terminals BP may be adjacent to the first sidewall SW1.The first dummy pad DPD1 may be closer (in a horizontal direction) tothe first sidewall SW1 than the outermost terminal BP1. In other words,when viewed in a plan view, a distance between the first dummy pad DPD1and the first sidewall SW1 may be smaller than a distance between theoutermost terminal BP1 and the first sidewall SW1.

A second dummy pad DPD2 of the dummy pads DPD may be adjacent to thesecond sidewall SW2. An outermost terminal BP2 of the first outerterminals BP may be adjacent to the second sidewall SW2. The seconddummy pad DPD2 may be closer (in a horizontal direction) to the secondsidewall SW2 than the outermost terminal BP2. In other words, whenviewed in a plan view, a distance between the second dummy pad DPD2 andthe second sidewall SW2 may be smaller than a distance between theoutermost terminal BP2 and the second sidewall SW2.

As can be seen from FIGS. 1 and 2, a set of dummy pads of the pluralityof dummy pads DPD may surround or be outside of an area occupied by anouter boundary of outermost interposer terminals BP of the interposersubstrate IPS, from a top-down view. Furthermore, outermost dummy padsof the plurality of dummy pads DPD may be horizontally closer to a sidesurface of the interposer substrate IPS than outermost interposerterminals BP of the interposer substrate IPS, from a top-down view.

A first distance L1 between the first sidewall SW1 and a center of theoutermost terminal BP1 (e.g., in the second direction D2) may range from300 μm to 1000 μm. Preferably, the first distance L1 ranges from 300 μmto 500 μm. A second distance L2 between the first sidewall SW1 and acenter of the first dummy pad DPD1 (e.g., in the second direction D2)may range from 100 μm to 800 μm. Preferably, the second distance L2ranges from 100 μm to 300 μm. A third distance L3 between a center ofthe outermost terminal BP1 and a center of the first dummy pad DPD1(e.g., in the second direction D2) may range from 50 μm to 200 μm.

Referring back to FIG. 3, the signal pad SPD may include a first lowerpad LPD1 on the first surface IPSa of the interposer substrate IPS and afirst upper pad UPD1 on the first lower pad LPD1. The connectionterminal IM may be disposed on the first upper pad UPD1. The first lowerpad LPD1 may be electrically connected to the conductive line CL of theinterposer substrate IPS.

The dummy pad DPD may include a second lower pad LPD2 on the firstsurface IPSa of the interposer substrate IPS and a second upper pad UPD2on the second lower pad LPD2. In some embodiments, the dummy pad DPD hasthe same size, shape, and/or structure of the signal pad SPD, and may beformed of the same materials as the signal pad SPD. For example, from atop-down view, the dummy pads DPD may each have a circular, rectangular,or other polygonal shape, and the signal pads may have the samecircular, rectangular, or other polygonal shape. The second upper padUPD2 may be exposed to the air during manufacturing, and may be coveredwith a protection layer or a mold layer in the completed package. Forexample, the second upper pad UPD2 of the dummy pad DPD may be coveredwith an insulating material. The second lower pad LPD2 may beelectrically disconnected from any conductive lines of the interposersubstrate IPS.

An insulating layer IL may be provided on the first surface IPSa of theinterposer substrate IPS. The insulating layer IL may be a passivationlayer covering the interposer substrate IPS. The insulating layer IL mayinclude a silicon oxide layer, a silicon nitride layer, or an insulatingpolymer layer, for example. A portion of a top surface of the firstlower pad LPD1 may be covered with the insulating layer IL. A portion ofa top surface of the second lower pad LPD2 may be covered with theinsulating layer IL.

A height from the first surface IPSa of the interposer substrate IPS tothe top surface of the first upper pad UPD1 may be a first height H1. Aheight from the first surface IPSa of the interposer substrate IPS tothe top surface of the second upper pad UPD2 may be a second height H2.The first height H1 and the second height H2 may be substantially equalto each other. Terms such as “same,” “equal,” “planar,” or “coplanar,”as used herein when referring to orientation, layout, location, shapes,sizes, compositions, amounts, or other measures do not necessarily meanan exactly identical orientation, layout, location, shape, size,composition, amount, or other measure, but are intended to encompassnearly identical orientation, layout, location, shapes, sizes,compositions, amounts, or other measures within acceptable variationsthat may occur, for example, due to manufacturing processes. The term“substantially” may be used herein to emphasize this meaning, unless thecontext or other statements indicate otherwise. For example, itemsdescribed as “substantially the same,” “substantially equal,” or“substantially planar,” may be exactly the same, equal, or planar, ormay be the same, equal, or planar within acceptable variations that mayoccur, for example, due to manufacturing processes.

In some embodiments, a ratio of a difference between the first andsecond heights H1 and H2 to the first height H1 (i.e., (H1−H2)/H1) maybe less than 0.2. For example, even where the first and second heightsH1 and H2 are not the same as each other, the ratio of a differencebetween the first and second heights H1 and H2 to the first height H1(i.e., (H1−H2)/H1) may be less than 0.05, or may range from 0.05 to 0.2.In example experimentation, even in a range for a ratio of (H1−H2)/H1 upto 0.2, package defects resulting from insufficiently heated outerinterposer terminals were greatly decreased.

As can be seen from FIGS. 1-3, in some embodiments, a first plurality ofsignal pads SPD each have a first height from their bottom surface totheir top surface, and the dummy pads DPD each have a second height fromtheir bottom surface to their top surface. The first height may be thesame as the second height.

The dummy pads described above may be formed of a thermally conductivematerial, which may also be an electrically conductive material. In someembodiments, each signal pad of a first plurality of signal pads whichcorrespond to a first semiconductor chip and a second plurality ofsignal pads which correspond to a second semiconductor chip is formed inpart or wholly of the same electrically conductive material that formsthe dummy pads.

FIG. 4 is an enlarged sectional view of a portion (e.g., the portion ‘M’of FIG. 2) of a semiconductor package according to an embodiment of theinventive concept. For concise description, elements previouslydescribed with reference to FIGS. 1 to 3 may be identified by the samereference number without repeating an overlapping description thereof.

Referring to FIG. 4, the signal pad SPD may include the first lower padLPD1 on the first surface IPSa of the interposer substrate IPS and thefirst upper pad UPD1 on the first lower pad LPD1. The insulating layerIL may be provided on the first surface IPSa. The dummy pad DPD mayinclude the second upper pad UPD2 on the insulating layer IL. Unlikethat described with reference to FIG. 3, the second lower pad LPD2 maybe omitted from the dummy pad DPD according to the present embodiment.The dummy pad DPD may be spaced apart from the first surface IPSa of theinterposer substrate IPS with the insulating layer IL interposedtherebetween.

A height from the first surface IPSa of the interposer substrate IPS toa top surface of the first upper pad UPD1 may be the first height H1. Aheight from the first surface IPSa of the interposer substrate IPS to atop surface of the second upper pad UPD2 may be the second height H2.The first height H1 and the second height H2 may be substantially equalto each other. In some embodiments, a ratio of a difference between thefirst and second heights H1 and H2 to the first height H1 (i.e.,(H1−H2)/H1) may be less than 0.05, or may range from 0.05 to 0.2.

A thickness of the first upper pad UPD1 (e.g., a maximum thickness in avertical direction, or a thickness from a surface of the first lower padLPD1 to a top surface of the first upper pad UPD1) may be a firstthickness T1. A thickness of the second upper pad UPD2 (e.g., a maximumthickness in a vertical direction, or a thickness from a surface of theinsulating layer IL to a top surface of the second upper pad UPD2) maybe a second thickness T2. The second thickness T2 may be greater thanthe first thickness T1. The second thickness T2 may be smaller than thesecond height H2.

A thickness of the signal pad SPD (e.g., a maximum thickness in avertical direction, or a thickness from a surface of conductive line CLto a top surface of the first upper pad UPD1) may be a third thicknessT3. A sum of the thickness (i.e., T1) of the first upper pad UPD1 and athickness of the first lower pad LPD1 may be the third thickness T3. Thethird thickness T3 may be substantially equal to the first height H1. Athickness of the dummy pad DPD may be the second thickness T2. Thesecond thickness T2 may be smaller than the third thickness T3.

FIGS. 5 and 6 are sectional views illustrating a method of fabricating asemiconductor package (e.g., of FIG. 1) according to an embodiment ofthe inventive concept. FIG. 7 is a sectional view illustrating a methodof fabricating a semiconductor package, according to a comparativeembodiment of the inventive concept. FIG. 13 is a flow chartillustrating an example method of manufacturing a semiconductor packagein accordance with certain embodiments. FIGS. 5, 6, and 13, and theircomparison to FIG. 7 are discussed below.

As shown in FIGS. 5, 6, and 13, in step 1301, a package substrate havinga bottom surface and a top surface is provided. For example, the packagesubstrate may be package substrate PSUB such as shown in FIGS. 1 and 2.In step 1302, a plurality of package terminals, such as second outerterminals SB, are provided on the bottom surface of the packagesubstrate PSUB. It should be noted, that although certain of the stepsof the method shown in FIG. 13 are described in a particular order, thesteps need not occur in that described order. For example, the pluralityof package terminals can be provided to the bottom surface of thepackage substrate PSUB either before subsequent steps (e.g., beforesteps 1303-1307), or after one or more of the subsequent steps (e.g.,after one of steps 1303, 1304, 1305, 1306, or 1307).

In step 1303, an interposer including an interposer substrate (e.g.,IPS) having a top surface (e.g., IPSa) and a bottom surface (e.g., IPSb)is provided. The interposer may include a plurality of interposerterminals BP disposed on the bottom surface of the interposer substrateIPS. The interposer may further include a first plurality of signal padsSPD disposed on the top surface IPSa of the interposer substrate IPS tooccupy a first area of the interposer substrate IPS, and electricallyconnected to wiring in the interposer substrate. The first plurality ofsignal pads SPD are configured for electrically connecting to one ormore circuits in a first semiconductor chip (e.g., DIE1). The interposerfurther includes a second plurality of signal pads disposed on the topsurface IPSa of the interposer substrate IPS to occupy a second area ofthe interposer substrate IPS, the second area horizontally separate fromthe first area, the second plurality of signal pads electricallyconnected to wiring in the interposer substrate IPS and for electricallyconnecting to one or more circuits in a second semiconductor chip (e.g.DIE2). The interposer further includes a plurality of dummy pads (e.g.,DPD) disposed outside of the first area and the second area from atop-down view and disposed on the top surface of the interposersubstrate.

In step 1304, the interposer substrate IPS is mounted on the top surfaceof the package substrate PSUB so that the plurality of interposerterminals BP are between the interposer substrate IPS and the packagesubstrate PSUB.

In step 1305, a heat bonding process is performed to bond the interposersubstrate IPS to the package substrate PSUB through the interposerterminals BP.

For example, referring to FIG. 5, the interposer substrate IPS may beprovided on the package substrate PSUB. In detail, the interposersubstrate IPS may be attached to a bottom surface of a heat-bonding headHD, and then, the interposer substrate IPS may be placed on the packagesubstrate PSUB using the head HD. The bottom surface of the head HD mayface the first surface IPSa of the interposer substrate IPS. The bottomsurface of the head HD may be in contact with the signal pads SPD andthe dummy pads DPD of the interposer substrate IPS.

Referring to FIG. 6, the interposer substrate IPS stacked on the packagesubstrate PSUB is compressed by the head HD. The compression of theinterposer substrate IPS may be performed during stacking the interposersubstrate IPS on the package substrate PSUB. The compression of theinterposer substrate IPS may include performing a thermo-compressionbonding process of applying heat and pressure to the interposersubstrate IPS. During the thermo-compression bonding process, heat andforce FT may be transferred from the head HD toward the first outerterminals BP through the signal pads SPD and the dummy pads DPD, some orall of which the head HD may contact. The first outer terminals BP maybe bonded to the package substrate PSUB by the heat and force FTtransferred to the first outer terminals BP. In certain embodiments,contacting the plurality of dummy pads with the heated heat-bonding headHD heats a portion of the interposer substrate outside of the areaoccupied by the first plurality of signal pads and outside of the areaoccupied by the second plurality of signal pads, which heat istransferred to the outermost interposer terminals of the plurality ofinterposer terminals BP. As a result of the heating of the signal padsSPD and dummy pads DPD, for signal pads or dummy pads that are connectedto a further metal component, an inter-metallic compound may be formedbetween the pad the further metal component. In some embodiments, adummy pad DPD or a signal pad SPD may be formed of a plurality of metallayers, and as a result of the thermos-compression heat bonding process,an inter-metallic compound may be formed between the different metallayers (e.g., wherein the compound is formed of the metals from thedifferent metals layers) so that the pad includes the different metallayers and the inter-metallic compound. For example, a pad may includean inter-metallic compound at an interface between two metal layers,such as an Au layer and an Ni layer, of the pad.

Referring back to FIG. 13, in step 1306, after performing the heatbonding process, a first semiconductor chip (e.g., DIE1) is mounted onthe top surface of the interposer substrate and the first semiconductorchip is connected to the first plurality of signal pads, and a secondsemiconductor chip is mounted on the top surface of the interposersubstrate and the second semiconductor chip (e.g., DIE2) is connected tothe second plurality of signal pads. The first semiconductor chip isdisposed to be horizontally separated from the second semiconductorchip. According to the certain embodiments, after these mountings, theplurality of dummy pads are outside of an area occupied by the firstsemiconductor chip and outside of an area occupied by the secondsemiconductor chip in a top down view. Also, in some embodiments, nodummy pads are on the top surface of the interposer substrate in an areabetween the first semiconductor chip and the second semiconductor chipin the top down view.

The plurality of dummy pads may be outside an area, in a top-down view,occupied by all of the interposer terminals on the bottom surface of theinterposer substrate. In some embodiments, none of the plurality ofdummy pads are connected to any wiring of the interposer substrate fortransmitting signals through the interposer substrate.

In step 1307, a molding layer formed of a molding material is formed toencapsulate at least the interposer substrate and the firstsemiconductor chip and second semiconductor chip. The molding materialmay cover and contact each dummy pad of the plurality of dummy pads. Forexample, the molding material may be a resin or other insulativemoldable material.

Referring to FIG. 7, the dummy pads DPD are omitted from the interposersubstrate IPS, unlike the interposer substrate IPS according to anembodiment of the inventive concept. A thermo-compression bondingprocess may be performed on the interposer substrate IPS through thehead HD. During the thermo-compression bonding process, the heat andforce FT may be transferred from the head HD toward the first outerterminals BP through the signal pads SPD. According to this comparativeembodiment, since the dummy pads DPD are omitted, the heat and force FTmay not be transferred to or may be reduced at an edge region of theinterposer substrate IPS. In this case, there may be a failure incontact or coupling between the first outer terminals BP and the packagesubstrate PSUB.

By contrast, according to embodiments of the inventive concept, the heatand force FT may be transferred through not only the signal pads SPD butalso the dummy pads DPD, which are disposed on the peripheral region PPRof the interposer substrate IPS, as previously described with referenceto FIG. 6. Thus, the heat and force FT from the head HD may be uniformlytransferred to the entire region of the interposer substrate IPS. As aresult, according to an embodiment of the inventive concept, it may bepossible to prevent a failure in contact or coupling between the firstouter terminals BP and the package substrate PSUB and to realize astable bonding structure.

According to the description of FIG. 2, the third distance L3 betweenthe outermost terminal BP1 and the first dummy pad DPD1 may range from50 μm to 200 μm. Since the distance between the outermost terminal BP1and the first dummy pad DPD1 is relatively short, the heat and force FTmay be effectively transferred from the first dummy pad DPD1 to theoutermost terminal BP1. If the third distance L3 between the first dummypad DPD1 and the outermost terminal BP1 is greater than 200 μm, the heatand force FT may not be effectively transferred from the first dummy padDPD1 to the outermost terminal BP1.

According to an embodiment of the inventive concept, the heat and forceFT from the head HD may be efficiently transferred toward the firstouter terminals BP through the conductive structure CS and the throughvias TV in the interposer substrate IPS, as previously described withreference to FIG. 2.

FIG. 8 is a perspective view illustrating a semiconductor packageaccording to an embodiment of the inventive concept. FIG. 9 is asectional view of the semiconductor package of FIG. 8. For concisedescription, elements previously described with reference to FIGS. 1 to3 may be identified by the same reference number without repeating anoverlapping description thereof.

Referring to FIGS. 8 and 9, the dummy pads DPD may include the firstdummy pads DPD1 adjacent to or closer to the center or central portion(e.g., either in the first direction D1 or the second direction D2) ofthe first surface IPSa of the interposer substrate IPS and the seconddummy pads DPD2 adjacent to a corner EG of the interposer substrate IPS.

The first dummy pads DPD1 may be disposed adjacent to the first signalregion SPR1, the second signal region SPR2, and the connection regionCNR. The first dummy pads DPD1 may be disposed between the first signalregion SPR1 and the second signal region SPR2, and therefore may behorizontally between the first semiconductor chip (DIE1) and the secondsemiconductor chip (DIE2) from the top-down view.

For example, the first dummy pads DPD1 may be dummy pads of theplurality of dummy pads DPD that are closest to the first and secondsignal regions SPR1 and SPR2 (e.g., closest to both of the first andsecond signal regions SPR1 and SPR2). The second dummy pads DPD2 may bedummy pads that are one of the dummy pads DPD and are farthest from thefirst and second signal regions SPR1 and SPR2. The second dummy padsDPD2 may be corner dummy pads. The second dummy pads of the plurality ofdummy pads, as well as another set of dummy pads (e.g., the dummy padsother than dummy pads DPD1 and DPD2) may be located outside of an areaoccupied by the first and second semiconductor chips and may not behorizontally between the first semiconductor chip and the secondsemiconductor chip.

A first dummy pad DPD1 and a second dummy pad DPD2 may be thermallyconnected to each other by a thermal line TL. Therefore, heat may betransferred from one of the first dummy pads DPD1 to one of the seconddummy pads DPD2 by thermal conduction through the thermal line TL. Thethermal line TL may be formed of a thermally and electrically conductivematerial and may be formed on or in the interposer substrate.

In detail, a first dummy pad DPD1 and a second dummy pad DPD2 may beconnected to each other through the conductive line CL (e.g., a metalline) in the interposer substrate IPS. In other words, the conductiveline CL connecting the first and second dummy pads DPD1 and DPD2 mayconstitute the thermal line TL. Alternatively, although not shown, afirst dummy pad DPD1 and a second dummy pad DPD2 may be electricallyconnected to each other through a metal line (e.g., the thermal lineTL), which is provided on the first surface IPSa of the interposersubstrate IPS.

As previously described with reference to FIG. 6, the heat, which istransferred from the head HD during the thermo-compression bondingprocess, may be mainly concentrated on a center region of the interposersubstrate IPS. As such, the heat may not be sufficiently transferred toa region near the corner EG of the interposer substrate IPS.

According to the embodiment of FIGS. 8 and 9, since the second dummy padDPD2 positioned near the corner EG of the interposer substrate IPS isthermally connected to the first dummy pad DPD1 positioned near thecenter of the interposer substrate IPS through the thermal line TL, theheat may be transferred from the center of the interposer substrate IPSto the corner EG of the interposer substrate IPS. As a result, the heatmay be uniformly transferred to the entire region of the interposersubstrate IPS, during the thermo-compression bonding process.

FIG. 10 is a plan view illustrating a semiconductor package according toan embodiment of the inventive concept. FIG. 11 is a plan viewillustrating a first surface of an interposer substrate of FIG. 10. FIG.12 is a sectional view taken along a line I-I′ of FIG. 10. For concisedescription, an element previously described with reference to FIGS. 1to 3 may be identified by the same reference number without repeating anoverlapping description thereof.

Referring to FIGS. 10, 11, and 12, the interposer substrate IPS may beprovided on the package substrate PSUB. The signal pads SPD may beprovided on the first signal region SPR1 and the second signal regionsSPR2 of the interposer substrate IPS. The dummy pads DPD may be providedon the peripheral region PPR of the interposer substrate IPS.

The interposer substrate IPS may include the conductive structure CS inthe second insulating layer IPS2, second through vias TV2 in the firstinsulating layer IPS1, and the conductive pads CPD in the thirdinsulating layer IPS3. The conductive structure CS may include aplurality of the conductive lines CL and a plurality of the vias VI.

A logic die SOC may be disposed on the first signal region SPR1 of theinterposer substrate IPS. A plurality of memory stacks SS may bedisposed on the second signal regions SPR2 of the interposer substrateIPS. A first chip that comprises the logic die SOC may be a single chipnot part of a stack of chips. A second chip that comprises one of thememory chips may be at the same height above the interposer substrate asthe first chip. For example, a pair of memory stacks SS may be disposedaround or near the logic die SOC. However, the inventive concept is notlimited to this example, and the number of the memory stacks SS may bevariously changed. Each of the memory stacks SS and the logic die SOCmay be mounted side by side (e.g., horizontally separated from eachother) on the interposer substrate IPS.

The logic die SOC may include a central processing unit CPU, a firstphysical-layer interface region PHY1, and a memory controller MCT. Forexample, the logic die SOC may be a system-on-chip. The logic die SOCmay be mounted on the interposer substrate IPS in a face-down manner(e.g., flip-chip manner), in which an active layer of the logic die SOCfaces the interposer substrate IPS.

A plurality of the memory stacks SS may have substantially the samestructure as each other. Hereinafter, one of the memory stacks SS willbe exemplarily described. The memory stack SS may include a buffer dieBC and first to fourth memory dies MC1-MC4, which are sequentiallystacked on the buffer die BC.

The buffer die BC may be mounted on the interposer substrate IPS in aface-down manner (e.g., flip chip manner), in which an active layer ofthe buffer die BC faces the interposer substrate IPS. The first tofourth memory dies MC1-MC4 may be dynamic random access memory (DRAM)chips. According to the present embodiment, the first to fourth memorydies MC1-MC4 may have substantially the same chip size. For example, thefirst to fourth memory dies MC1-MC4 may be provided to havesubstantially the same planar shape and substantially the same planararea.

Each of the first to third memory dies MC1, MC2, and MC3 may includefirst through vias TV1, which are provided to penetrate the same. Thefourth memory die MC4 may not include the first through via TV1. Microbumps MBP may be provided between the buffer die BC and the first memorydie MC1, between the first memory die MC1 and the second memory die MC2,between the second memory die MC2 and the third memory die MC3, andbetween the third memory die MC3 and the fourth memory die MC4.

The micro bumps MBP may be electrically connected to the first throughvias TV1 of the first to third memory dies MC1, MC2, and MC3. The firstto fourth memory dies MC1-MC4 may be electrically connected to thebuffer die BC through the first through vias TV1 and the micro bumpsMBP.

The connection terminals IM may be respectively interposed between thelogic die SOC and the signal pads SPD on the first signal region SPR1.The connection terminals IM may be respectively interposed between thebuffer die BC of the memory stack SS and the signal pads SPD on thesecond signal region SPR2. As an example, the connection terminals IMmay include micro bumps.

The buffer die BC of the memory stack SS may include a secondphysical-layer interface region PHY2. Data lines IOd may be providedbetween the first physical-layer interface region PHY1 of the logic dieSOC and the second physical-layer interface region PHY2 of the bufferdie BC. Data may be exchanged between the logic die SOC and the bufferdie BC through the data lines IOd. Conductive lines in the interposersubstrate IPS may constitute the data lines IOd. The data lines IOd maybe disposed below the connection region CNR of the interposer substrateIPS.

Referring back to FIGS. 11 and 12, the dummy pads DPD may be disposed ina remaining region of the first surface IPSa, other than the first andsecond signal regions SPR1 and SPR2 and the connection region CNR. Theoutermost one of the dummy pads DPD, which is adjacent to a sidewall ofthe interposer substrate IPS, may be horizontally closer to the sidewallthan the outermost one of the first outer terminals BP, which isadjacent to the sidewall of the interposer substrate IPS.

As described herein, certain areas may be described from a top down viewto describe the location of certain components. For example, thespecification may refer to an area “occupied” by a semiconductor chip orby a plurality of pads or plurality of terminals. The use of this termin connection with a semiconductor chip refers to the area that the chiptakes up, e.g., between boundaries formed by the edges of the chip, froma top down view. With respect to a set or plurality of terminals or aset or plurality of pads, an area “occupied” by the set or plurality ofpads or terminals refers to an area including outermost pads orterminals of the set or plurality of pads or terminals and all spacewithin boundaries created by the outermost pads or terminals.

The connection terminals IM are provided on the signal pads SPD,respectively. However, the connection terminals IM are not be providedon the dummy pads DPD. The signal pads SPD on the first signal regionSPR1 may be vertically overlap the logic die SOC thereon. The signalpads SPD on the second signal region SPR2 may vertically overlap thememory stack SS thereon. In one embodiment, the dummy pads DPD do notvertically overlap either of the logic die SOC or the memory stack SS.When viewed in a plan view, the dummy pads DPD may be spaced apart fromboth of the logic die SOC and the memory stack SS.

Meanwhile, although not shown, the dummy pads DPD more adjacent to thecenter of the interposer substrate IPS may be connected to the dummypads DPD adjacent to the corner of the interposer substrate IPS throughthe thermal line TL, similar to that previously described with referenceto FIGS. 8 and 9.

According to various embodiments of the inventive concept, a dummy padof an interposer substrate is used to prevent a failure in contact orcoupling between the interposer substrate and a package substrate of asemiconductor package. As a result, it may be possible to realize asemiconductor package with improved electric characteristics.

Ordinal numbers such as “first,” “second,” “third,” etc. may be usedsimply as labels of certain elements, steps, etc., to distinguish suchelements, steps, etc. from one another. Terms that are not describedusing “first,” “second,” etc., in the specification, may still bereferred to as “first” or “second” in a claim. In addition, a term thatis referenced with a particular ordinal number (e.g., “first” in aparticular claim) may be described elsewhere with a different ordinalnumber (e.g., “second” in the specification or another claim).

While example embodiments of the inventive concepts have beenparticularly shown and described, it will be understood by one ofordinary skill in the art that variations in form and detail may be madetherein without departing from the spirit and scope of the attachedclaims.

We claim:
 1. A semiconductor package comprising: a package substratehaving a bottom surface and a top surface; a plurality of packageterminals disposed on the bottom surface of the package substrate; aninterposer substrate disposed on the top surface of the packagesubstrate, the interposer substrate having a bottom surface facing thepackage substrate and a top surface opposite the bottom surface; aplurality of interposer terminals disposed on the bottom surface of theinterposer substrate and electrically connected to the packagesubstrate; a first semiconductor chip disposed on the top surface of theinterposer substrate; a second semiconductor chip disposed on the topsurface of the interposer substrate and disposed to be horizontallyseparated from the first semiconductor chip; a first plurality of signalpads disposed on the top surface of the interposer substrate andelectrically connected to wiring in the interposer substrate and one ormore circuits in the first semiconductor chip; a second plurality ofsignal pads disposed on the top surface of the interposer substrate andelectrically connected to wiring in the interposer substrate and to oneor more circuits in the second semiconductor chip; and a plurality ofdummy pads disposed outside of an area occupied by the firstsemiconductor chip from a top-down view and outside of an area occupiedby the second semiconductor chip from a top-down view and disposed onthe top surface of the interposer substrate, wherein the first pluralityof signal pads, the second plurality of signal pads, and the pluralityof dummy pads are all located at the same vertical height above the topsurface of the package substrate, wherein each pad of the firstplurality of signal pads and the second plurality of signal pads isconfigured to transfer signals between the interposer substrate and arespective semiconductor chip, wherein each pad of the dummy pads is notconfigured to transfer signals between the interposer substrate and anysemiconductor chip disposed thereon, wherein at least a first dummy padof the plurality of dummy pads is located horizontally between the firstsemiconductor chip and the second semiconductor chip, and wherein atleast a second dummy pad of the plurality of dummy pads is locatedoutside of an area occupied by the first and second semiconductor chipsand not horizontally between the first semiconductor chip and the secondsemiconductor chip.
 2. The semiconductor package of claim 1, wherein: aset of dummy pads of the plurality of dummy pads surround an areaoccupied by an outer boundary of outermost interposer terminals of theinterposer substrate, from a top-down view.
 3. The semiconductor packageof claim 1, wherein: outermost dummy pads of the plurality of dummy padsare horizontally closer to a side surface of the interposer substratethan outermost interposer terminals of the interposer substrate, from atop-down view.
 4. The semiconductor package of claim 1: wherein thefirst dummy pad is thermally connected to the second dummy pad by athermal line.
 5. The semiconductor package of claim 4, wherein: thethermal line is formed of a thermally and electrically conductivematerial and is formed on or in the interposer substrate.
 6. Thesemiconductor package of claim 1, wherein: the dummy pads areelectrically isolated from any wiring or circuits in the interposersubstrate.
 7. The semiconductor package of claim 1, wherein: the dummypads have a bottom surface facing the interposer substrate and a topsurface facing away from the interposer substrate, and the top surfaceof each dummy pad contacts an insulating material and does not contactan electrically conductive material.
 8. The semiconductor package ofclaim 7, wherein: the insulating material is a molding material formedto encapsulate the semiconductor package.
 9. The semiconductor packageof claim 1, wherein: the dummy pads have a bottom surface facing theinterposer substrate and a top surface facing away from the interposersubstrate, and the bottom surface of each dummy pad contacts aninsulating material and does not contact an electrically conductivematerial.
 10. The semiconductor package of claim 1, wherein: the firstplurality of signal pads each have a first height from their bottomsurface to their top surface, the dummy pads each have a second heightfrom their bottom surface to their top surface, and the first height isthe same as the second height.
 11. The semiconductor package of claim 1,further comprising: a first connection region horizontally between thefirst semiconductor chip and the second semiconductor chip; andconductive lines formed in or on the interposer substrate in the firstconnection region, wherein no dummy pads are formed on the top surfaceof the interposer substrate above the conductive lines in the firstconnection region.
 12. The semiconductor package of claim 1, wherein:the second dummy pad is one of a plurality of second dummy pads locatedoutside of the area occupied by the first and second semiconductor chipsand not horizontally between the first semiconductor chip and the secondsemiconductor chip; the plurality of second dummy pads are arranged infirst and second directions respectively parallel to a first edge of theinterposer substrate and a second edge of the interposer substrateperpendicular to the first edge; and adjacent dummy pads of theplurality of second dummy pads in each of the first direction and seconddirection are separated from each other by no more than 200 μm.
 13. Thesemiconductor package of claim 1, wherein: the first plurality of signalpads are arranged in first and second directions respectively parallelto a first edge of the interposer substrate and a second edge of theinterposer substrate perpendicular to the first edge; and adjacentsignal pads of the first plurality of signal pads in each of the firstdirection and second direction are separated from each other by no morethan 150 μm.
 14. The semiconductor package of claim 1, wherein: thefirst semiconductor chip is a logic chip; and the second semiconductorchip is a die of a memory stack.
 15. The semiconductor package of claim14, wherein: the first semiconductor chip is a single chip not part of astack of chips; and the second semiconductor chip is at the same heightabove the interposer substrate as the first semiconductor chip.
 16. Asemiconductor package comprising: a package substrate having a bottomsurface and a top surface; a plurality of package terminals disposed onthe bottom surface of the package substrate; an interposer substratedisposed on the top surface of the package substrate, the interposersubstrate having a bottom surface facing the package substrate and a topsurface opposite the bottom surface; a plurality of interposer terminalsdisposed on the bottom surface of the interposer substrate andelectrically connected to the package substrate; a first semiconductorchip disposed on the top surface of the interposer substrate; a secondsemiconductor chip disposed on the top surface of the interposersubstrate and disposed to be horizontally separated from the firstsemiconductor chip; a first plurality of signal pads disposed on the topsurface of the interposer substrate and electrically connected to wiringin the interposer substrate and one or more circuits in the firstsemiconductor chip; a second plurality of signal pads disposed on thetop surface of the interposer substrate and electrically connected towiring in the interposer substrate and to one or more circuits in thesecond semiconductor chip; and a plurality of dummy pads disposedoutside of an area occupied by the first semiconductor chip from atop-down view and outside of an area occupied by the secondsemiconductor chip from a top-down view and disposed on the top surfaceof the interposer substrate, wherein the first plurality of signal pads,the second plurality of signal pads, and the plurality of dummy pads areall located at the same vertical height above the top surface of thepackage substrate, and wherein a set of dummy pads of the plurality ofdummy pads are outside of an area occupied by an outer boundary ofoutermost interposer terminals of the interposer substrate, from atop-down view, wherein each pad of the first plurality of signal padsand the second plurality of signal pads are for transferring signals;and wherein each pad of the plurality of dummy pads is electricallyisolated at its top surface by an insulating material.
 17. Thesemiconductor package of claim 16, wherein: each pad of the plurality ofdummy pads does not transfer signals.
 18. The semiconductor package ofclaim 16, wherein: each dummy pad of the plurality of dummy pads isconnected to a dummy TSV passing through the interposer substrate. 19.The semiconductor package of claim 16, wherein the insulating materialis a molding layer formed of a molding material that encapsulates atleast the interposer substrate and the first semiconductor chip andsecond semiconductor chip, wherein the molding material covers andcontacts each dummy pad of the plurality of dummy pads.
 20. Asemiconductor package comprising: a package substrate having a bottomsurface and a top surface; a plurality of package terminals disposed onthe bottom surface of the package substrate; an interposer substratedisposed on the top surface of the package substrate, the interposersubstrate having a bottom surface facing the package substrate and a topsurface opposite the bottom surface; a plurality of interposer terminalsdisposed on the bottom surface of the interposer substrate andelectrically connected to the package substrate; a first semiconductorchip disposed on the top surface of the interposer substrate; a secondsemiconductor chip disposed on the top surface of the interposersubstrate and disposed to be horizontally separated from the firstsemiconductor chip; a first plurality of signal pads disposed on the topsurface of the interposer substrate and electrically connected to wiringin the interposer substrate and one or more circuits in the firstsemiconductor chip; a second plurality of signal pads disposed on thetop surface of the interposer substrate and electrically connected towiring in the interposer substrate and to one or more circuits in thesecond semiconductor chip; a first dummy pad disposed horizontallybetween the first semiconductor chip and the second semiconductor chip;a second dummy pad disposed outside of an area occupied by the first andsecond semiconductor chips; and a thermal line thermally connecting thefirst dummy pad to the second dummy pad.